Apparatus for forming an image and corresponding methods

Abstract

Disclosed are an apparatus, optical scanning device, and a corresponding method of forming images on a photosensitive surface. The apparatus includes a laser raster output scanner (ROS) including laser emitters arranged to simultaneously scan a plurality of laser beams across a single scan line of the photosensitive surface in response to received image data corresponding to pixels in an image to be reproduced, and a controller individually controlling each of the laser emitters to selectively apply one of a plurality of power levels to each of the laser beams based on the image data for each of the pixels, wherein a total power applied by the laser beams for each pixel is determined by a sum of the power levels applied by each of the laser beams.

1. An apparatus for forming an image on a photosensitive surface, comprising: a laser raster output scanner (ROS) including laser emitters arranged to simultaneously scan a plurality of laser beams across a single scan line of the photosensitive surface in response to received image data corresponding to pixels in an image to be reproduced; and a controller individually controlling each of the laser emitters to selectively apply one of a plurality of power levels to each of the laser beams based on the image data for each of the pixels, wherein a total power applied by the laser beams for each pixel is determined by a sum of the power levels applied by each of the laser beams, wherein the controller selects either the power levels for each of the laser emitters for each pixel from among five different power levels, or selects the power levels for each of the laser emitters to achieve a total power level applied to each pixel from among sixteen different total power levels, the sixteen different total power levels being substantially linearly spaced. 
     
     
       2. The apparatus of  claim 1 , wherein the laser emitters are arranged so as to simultaneously scan the plurality of laser beams across each of a plurality of scan lines. 
     
     
       3. The apparatus of  claim 1 , wherein the laser raster output scanner comprises thirty-two light emitters arranged so as to simultaneously scan thirty-two laser beams across eight scan lines, wherein four different ones of the thirty-two laser beams are simultaneously scanned across each of the eight scan lines. 
     
     
       4. The apparatus of  claim 1 , wherein the controller controls an on time and an off time of the laser emitters as they scan individual ones of the pixels to further control a total power level applied to each pixel. 
     
     
       5. A method of forming images on a photosensitive surface with an apparatus having a laser raster output scanner (ROS) including laser emitters, comprising: simultaneously scanning a plurality of laser beams emitted from the laser emitters across a single scan line of the photosensitive surface in response to received image data corresponding to pixels in an image to be reproduced; and individually controlling each of the laser emitters to selectively apply one of a plurality of power levels to each of the laser beams based on the image data for each of the pixels, wherein a total power applied by the laser beams for each pixel is determined by a sum of the power levels applied by each of the laser beams; selecting either the power levels for each of the laser emitters for each pixel from among five different power levels; or selecting the power levels for each of the laser emitters to achieve a total power level applied to each pixel from among sixteen different total power levels, wherein the sixteen different total power levels are substantially linearly spaced. 
     
     
       6. The method of  claim 5 , wherein the plurality of laser emitters are arranged so as to simultaneously scan the plurality of laser beams across each of a plurality of scan lines. 
     
     
       7. The method of  claim 5 , wherein the laser raster output scanner comprises thirty-two light emitters arranged so as to simultaneously scan thirty-two laser beams across eight scan lines, wherein four different ones of the thirty-two laser beams are simultaneously scanned across each of the eight scan lines. 
     
     
       8. The method of  claim 5 , further comprising controlling an on time and an off time of the laser emitters as they scan individual ones of the pixels to further control a total power level applied to each pixel. 
     
     
       9. An optical scanning device for forming an image on a photosensitive surface, comprising: a laser raster output scanner (ROS) including laser emitters that simultaneously scan a plurality of laser beams across a single scan line of the photosensitive surface; and a controller individually controlling each of the laser emitters based on image data to apply one of a plurality of power levels from each of the laser beams to each of a plurality of pixels across the scan line, wherein the controller controls a power level of each of the laser beams to selectively apply one of a plurality of gray levels to each of the pixels, wherein the controller selects either the power levels for each of the laser emitters for each pixel from among five different power levels, or selects the power levels for each of the laser emitters to achieve a total power level applied to each pixel from among sixteen different total power levels, the sixteen different total power levels being substantially linearly spaced. 
     
     
       10. The optical scanning device of  claim 9 , wherein the laser raster output scanner simultaneously scans thirty-two laser beams across eight scan lines, wherein four different ones of the thirty-two laser beams are simultaneously scanned across each of the eight scan lines. 
     
     
       11. The optical scanning device of  claim 9 , wherein the controller controls an on time and an off time of the laser emitters as they scan individual ones of the pixels to further control the total power level applied to each pixel.